Method and apparatus for testing certain characteristics of paper and the like



Nov. 26, 1968 F. F. OEHME ET AL 3,412,605

METHOD AND APPARATUS FOR TESTING CERTAIN CHARACTERISTICS OF PAPER ANDTHE LIKE Filed Nov. 30, 1966 3 Sheets-Sheet 1 In 1/2 )2 tor-9 HANK FOEHME MIC/{A65 L. 5WAN50N B 2% pm%wm 9 6m Adj/5 Nov. 26, 1968 F. F.OEHME ET AL 3,412,605

METHOD AND APPARATUS FOR TESTING CERTAIN CHARACTERISTICS OF PAPER ANDTHE LIKE Filed Nov. 30, 1966 3 Sheets-Sheet 2 FQA/v/(E OEHME Mich A61 L.SWAAAEON B 514%, W 1m vAMJ/km United States Patent 3,412,605 METHOD ANDAPPARATUS FOR TESTING CER- CHARACTERISTICS OF PAPER AND THE Frank F.Oehme and Michael L. Swanson, Wisconsin Rapids, Wis., assignors toConsolidated Papers, Inc., Wisconsin Rapids, Wis., a corporation ofWisconsin Filed Nov. 30, 1966, Ser. No. 598,037 13 Claims. (Cl. 73-150)ABSTRACT OF THE DISCLOSURE An improved method and apparatus for testingthe piling propensity of paper or the like where a specimen of the paperto be tested is mounted on one of a pair of opositely disposed anvilmembers and the two anvil members are moved into face-to-face engagementunder pressure and one of the anvil members is then rotated about itslongitudinal axis relative to the other anvil member, after which one ofthe anvil members is suddenly moved axially away from the other anvilmember, thereby subjecting the test specimen to both rubbing and pickforces in a predetermined timed sequence.

The present invention relates to a method and apparatus for testingcertain characteristics of paper, and it is particularly useful intesting the piling propensity of coated offset papers.

In web offset printing, a Web of paper is conducted over an offsetroller or cylinder having a blanket thereon which picks up ink from aprinting plate and applies it to the paper. Where both sides of thepaper are being printed simultaneously, the web of paper may beconducted through a nip formed by two adjacent blanket cylinders,Whereas if only one side of the paper is being printed the web may beconducted through a nip formed between an offset blanket cylinder and animpression roller. The considerations to be discussed below apply toeach of the foregoing situations, but for purposes of discussion we willconsider the application where a paper web is conducted between a pairof offset blanket rollers for printing simultaneously on both sides ofthe web.

It is -well known in the art of printing on a multicolor offsetlithographic press that a specially treated printing cylinder isprepared having an image formed thereon, and water or fountain solutionis applied to the printing cylinder. In the image or printing areas ofthe cylinder the water is repelled, whereas the water remains on thenonimage areas of the cylinder. Consequently, when ink is applied to theprinting cylinder, the ink remains on the image or printing areas and isrepelled by the water in the nonimage areas. Thereafter, when theprinting cylinder contacts the offset blanket, it applies ink to theblanket in the image areas while applying water or fountain solution tothe nonimage areas.

One of the most serious problems encountered in offset printing is knownas piling and constitutes the contamination of the offset blanket withpartially water soluble material from the coated offset papers beingprinted. Such a phenomenon usually occurs on one or more units ofmulticolor offset lithographic presses where partially water solublecoating material from coated offset papers contaminates the offsetblanket, there being a gradual building up or piling of such material onthe blanket during an accumulative process whihc develops with thenumber of printing impressions and is dependent upon the wet resistanceof the paper and various printing press variables.

When two adjacent blanket cylinders press against one another at the nipdefined therebetween, the blankets become slightly flattened so as toreduce the radius of each blanket at the contact area thereby causing aslightly lower peripheral speed at such area. The foregoing effect canproduce a rubbing or frictional force between the blankets and a web ofpaper passing through the nip thereby causing contamination of theblankets with coating material from the paper. Similar rubbing orfrictional forces between the blankets and the paper web can also beproduced where due to the foregoing flattening of the blankets or forother reasons the radii of two adjacent blanket cylinders are not quiteequal to one another at the contact area. Another cause of piling occurswhen a blanket is not wrapped on its cylinder with suflicient tension sothat a wrinkle or the like develops which moves around the periphery ofthe cylinder producing rubbing between the blanket and the paper webpassing thereover. Friction between the blanket and the paper web isalso sometimes produced by a lubricating effect caused by any inbalanceof the ink and water on the blanket.

In addition to the various causes of piling or contamination of ablanket with coating material from offset coated papers due to rubbingbetween the blanket and the paper web, another quite different cause ofpiling relates to the picking action which occurs when the paper web ispeeled away from the blanket. When the paper web leaves the nip betweentwo blanket cylinders it will tend to follow one of the blankets,usually the one having the most ink thereon, and the web as it movesalong its predetermined path is stripped or peeled away from the blanketcausing a picking action which again may tend to cause some of thecoating material on the paper to adhere to the blanket.

From the foregoing discussion it will be seen that piling is produceddue to rubbing or friction between the paper web and the blankets as theweb passes through the nip defined therebetween, and in addition due toa picking action as the web leaves the nip and is peeled away from theblankets. We have found that both rubbing and picking forces aresignificant causes of piling on the nonimage areas of a blanket, whilepicking appears to constitute the major cause of piling on the imageareas, the reason for the latter being that the lubricating effect ofthe ink tends to reduce piling caused by rubbing or friction in theimage areas.

The piling or transfer of coating material from coated offset papers toa printing blanket is known to cause various serious problems after ithas had an opportunity to accumulate on the blanket. For example, pilingcan decrease blanket life and make the blanket difficult to clean, andit can also affect the operation of the printing plates. Theeffectiveness of the fountain solution may also be reduced with theresult that some ink may be present in the nonimage areas of theprinting plate and on the blanket. Moreover, when there is anaccumulation of coating material on the image areas of the blanket, theresult may be that all of the ink will not be transferred to the paper,thereby producing a piling of ink on the blanket.

The most effective known means for avoiding the foregoing and otherproblems caused by piling is to control the offset paper during themanufacture thereof so as to reduce its piling propensity, and in orderto accomplish this it is necessary to have available a reliable test fordetermining the piling propensity of coated offset paper. It is known inthe art to conduct a wet pick test in order to determine the pilingpropensity of paper, and one such test method and apparatus aredescribed in US. Patent 3,129,586, which is assigned to the assignee ofthe present invention. However, a wet pick test is not sufficientlyaccurate because it does not indicate the piling propensity of paperwhen subjected to a rubbing action, and thus it is particularlyinadequate as an indication of piling in the nonimage'areas of a blanketwhere both rubbing and picking forces are significant causes of piling.It is also known to conduct a wet rub test as an indication of thepiling propensity of paper, but such a test is deficient as a trueindication of piling propensity both as to the image areas and thenonimage areas of a blanket because it does not take into account pilingproduced by a picking action.

It should further be understood that some types of coated offset paperswill show a high resistance to piling in a pick test, and a lowresistance to piling in a rub test, or vice versa, and thus such testsdo not provide an accurate indication as to what the piling propensityof the paper will be when subjected to rubbing or frictional forces andpicking forces during an actual printing operation. Moreover, it isimportant to note that merely to conduct separate wet pick tests and wetrub tests on samples of offset papers would still not provide reliableresults, since in an actual printing operation the rubbing or frictionalforces and the pick forces occur in a cer tain sequence and timerelationship which effects the degree of piling resulting from thecombination thereof.

It is therefore a general object of the present invention to provide animproved method for determining the piling propensity of paper bysimulating the combined effect of rubbing forces and pick forces in asingle test thereby providing an unusually reliable indication of thedegree of piling which will occur in an actual printing operation.

Another object of the invention is to provide apparatus for carrying outthe foregoing method including a pair of anvil members one of whichmoves toward and away from the other to produce picking forcestherebetween, and one of which is rotatable relative to the other toproduce rubbing forces therebetween.

A further object of the invention is to provide apparatus which appliesrubbing or frictional forces and pick forces to a test sample in apredetermined timed sequence so as to approximately duplicate the timingof application of such forces to a paper web during an actual printingoperation.

The foregoing and other objects and advantages of the invention will beapparent from the following description thereof.

Now, in order to acquaint those skilled in the art with the manner ofpracticing the method of the present invention and making and using theapparatus thereof, we shall describe, in conjunction with theaccompanying drawings, certain preferred embodiments of the invention.

In the drawings:

FIGURE 1 is an elevational view showing test apparatus constructed inaccordance with the teachings of the present invention;

FIGURE 2 is a plan view of the lower portion of the apparatus lookingapproximately in the direction of the arrows 22 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary vertical sectional view, partly inelevation, taken substantially along the line 33 of FIGURE 1; and

FIGURE 4 is a schematic electrical wiring diagram of the controls forthe apparatus of FIGURE 1.

Referring now to the drawings, FIGURE 1 shows an upright post fromwhich, there is supported a vertically disposed air cylinder 12. Apiston rod 14 extends downwardly from the lower end of the cylinder 12and carries an upper anvil member 16 thereon. The piston rod 14 isnormally in an upper or retracted position as shown in FIGURE 1 and ismovable downwardly during a testing cycle, as will appear more fullylater herein. A pedestal 18 is disposed beneath the upper anvil 16, anda baseplate 20 is screwed or otherwise fixedly secured to the top of thepedestal 18, the baseplate 20 including a base member 22 and a pair ofupright end walls 24 and 26.

A generally U-shaped integral bearing housing 28 comprises a horizontalupper wall 30, a pair of vertical side walls 32 and 34, and a pair ofhorizontal mounting flanges 36 and 38 extending outwardly from the sidewalls and permitting the housing to be fixedly secured to the baseplate20 by a plurality of cap screws or the like 40. A lower anvil 42 isrotatably carried immediately above the wall 30 of the bearing housingand is driven by an air cylinder 44 and reciprocating rack member 46.The air cylinder 44 has a piston rod 48 which is connected to one end ofthe rack 46 by an adapter 50, and upon operation of the cylinder 44 topush the rack 46 to the right as viewed in FIGURE 1, the rack acts torotate the lower anvil 42 in a manner to be described more fully laterherein.

The degree of rotation of the lower anvil 42 is controlled by anadjustable stop screw 52 which limits the linear stroke of the rack 46.The stop screw 52 is threaded through the baseplate end wall 26 and isprovided with a knurled knob 54 at one end thereof so that by manuallyrotating the screw its longitudinal position may be adjusted to vary thestroke of the rack member 46, the latter being in alignment with thestop screw for engagement therewith. A knurled nut 56 is threaded on thescrew 52 and may be rotated into engagement with a boss 58 fixed t0 thebaseplate wall 26 in order to lock the stop screw in a selectedposition. In addition, an indicator wheel 60 is fixed to the stop screw52 for rotation therewith, and a scale 62 is supported from thebaseplate 20 by a bracket 64. The indicator wheel 60 and scale 62 serveto indicate the position of the stop screw 52 which in turn controls thedegree of rotation of the lower anvil 42, and the scale 62 is preferablymarked in degrees or in turns, e.g., from 0 to 2 turns, so as tofacilitate positioning of the adjustable stop screw in accordance withthe desired rotation of the lower anvil.

As best shown in FIGURE 3, the lower anvil 42 has integral therewith amounting shaft comprising a first shaft section 64 and a reduceddiameter shaft section 66. The shaft section 64 is journaled in an upperbushing 68 which is pressed into an opening in the Wall 30 of thehousing 28, and the lower shaft section 64 is journaled in a lowerbushing 70 which is pressed into an opening in the baseplate 22. A ballthrust bearing 72 is positioned on the shaft section 66 immediatelyabove the baseplate 22, and a spur gear 74 having a plurality ofperipheral gear teeth 76 is located on the shaft section 66 above thethrust bearing 72. The spur gear 74 is keyed to the shaft section 66 bya key member 78 so that rotation of the spur gear will cause rotation ofthe lower anvil 42. A collar 80 is positioned on the lower end of theshaft section 64 beneath the upper bushing 68 and is fixed to the shaftby means of a set screw 82.

It will be understood from the foregoing that any downward force on theanvil 42 will be transmitted by the lower end of the shaft section 64 tothe spur gear 74 and then to the ball thrust bearing 72, and in thismanner the lower anvil 42 is supported so as to be spaced a shortdistance above the wall 30 of the bearing housing 28, the anvil thusbeing free to rotate upon rotation of the spur gear 74. A dial 84 (seeFIGURE 2) is mounted on the top of the housing plate 30 beneath thelower anvil 42, and the dial extends around the periphery of the anvilso as to provide an indication of the rotary movement thereof. Thus, theanvil 42 may have a reference mark on the side thereof, and the dial 84may be graduated in fractions of a turn. Assuming the reference mark onthe anvil 42 is initially aligned with a start position on the dial 84,the location of the reference mark relative to the dial after rotationof the anvil 42 will indicate the angle through which the anvil hasrotated, thus providing a check as to the setting of the adjustable stopscrew 52.

A shaft 86 is mounted in spaced parallel relation to the anvil shaft 64,66, the shaft 86 being disposed intermediate the anvil shaft and therack member 46. The upper end of the shaft 86 is journaled in a bushing88 which is pressed into an opening in the housing plate 30, and thelower end of the shaft 86 is journaled in a bushing 90 which is pressedinto an opening in the baseplate 22. The shaft 86 is formed with anintegral collar 92, and a spur gear 94 is mounted on the shaftimmediately above the collar and is keyed to the shaft for rotationtherewith by means of a key member 96. The spur gear 94 has a pluralityof peripheral teeth 98 which mesh with a plurality of teeth 100 formedon the rack member 46. A guide bar 102 is fixed to the baseplate 22 by aplurality of screws 104, and the rack member 46 moves in a linear pathbetween the guide bar and the spur gear 94 so as to be held in drivingengagement with the latter.

A second spur gear 106 is mounted on the shaft 86 above thefirst-mentioned spur gear 94 and is keyed to the shaft for rotationtherewith by a key member 108. The spur gear 106 is substantially largerin diameter than the spur gear 94 and is provided with a plurality ofperipheral teeth 110 which mesh with the teeth 76 formed on the spurgear 74. It will now be understood that when the air cylinder 44 isactuated so as to push the rack member 46 to the right as viewed inFIGURES 1 and 2, until the end of the rack abuts the end of the stopscrew 52, the rack 46 will act through the spur gears 98, 106, and 74 torotate the lower anvil 42 through a predetermined angle of rotationdependent upon the stroke of the rack member as controlled by theadjustable stop screw 52.

The lower anvil 42 has a layer of double-faced adhesive tape 112 appliedto the top thereof, and a discshaped anvil plate 114 is mounted on thetop of the tape. The tape 112 thus serves as an electrical insulatorbetween the lower anvil 42 and the anvil plate 114, and as will be morefully understood hereinafter such an insulator or dielectric isnecessary when the apparatus is used for penetration testing. A piece ofoffset blanket material 116 is attached to the bottom surface of theupper anvil 16 with double-faced pressure sensitive tape or any othersuitable adhesive means.

In conducting a test of a sample piece of coated paper, the test sampleis preferably attached by double-faced pressure sensitive tape or thelike to the blanket 116 at the bottom of the upper anvil 16. The blanket116 provides a relatively permanent cushion which compensates forsurface irregularities of the test sample and small variations incontact between the upper anvil 16 and the lower anvil plate 114. Asmall piece of black plastic electricians tape or other suitablematerial, preferably dark in color, is placed on the upper surface ofthe rotatable lower anvil plate 114, and a single drop of aqueoussolution such as lithographic fountain solution is placed on theelectricians tape directly under the upper anvil 16.

During a test cycle the upper anvil 16 is moved downwardly intoengagement with the lower anvil plate 114, thus pressing the test samplebetween the two anvils, more specifically, between the blanket 116 onthe upper anvil 16 and the black tape on the lower anvil plate 114,causing the fountain solution to be spread over the contact area so thatany excess moisture is squeezed out. A predetermined time after theupper anvil 16 engages against the lower anvil plate 114, the loweranvil plate is rotated through a predetermined angle, after which theupper anvil is suddenly retracted upwardlyat a controlled speed so as toseparate the test sample from the black tape on the lower anvil plate.Finally, the lower anvil plate 114 is rotated back to its originalposition. The piling propensity of the test sample is determined byexamination of the black tape so as to measure the amount of coatingmaterial which has been transferred thereto from the test sample, thecoating material being more or less white in color and thus beingreadily visible on the tape.

The foregoing test cycle and the control apparatus for regulating thesame will now be described in greater detail in conjunction with FIGURE4. A function switch 118 has a three-position switch arm 120 movable forcooperation with a selected one of three terminals 122, 124 and 126. Thearm 120 is moved to the upper terminal 122 for a penetration test, aswill be described later herein; it is moved to the lower terminal 126for pick tests and combination pick-rub, as will be describedhereinbelow; and the center terminal 124 is the off position.

A combination pick-rub test will now be described and it will thus beassumed that the function switch arm 120 is engaged with the terminal126. In order to initiate a test the operator closes a main power switch128 and manually presses a start push button 130 to its closed positionso as to complete a circuit through lines 132, 134, 136, 138 and 140 toa four-way solenoid valve 142 which is integral with the air cylinder12. The valve 142 is normally positioned so that the piston rod 14 andupper anvil 16 are in their upper or retracted positions, and completionof the circuit as described above initiates downward movement of theanvil 16.

It will be noted that when the start button 130 is closed it alsocompletes a circuit through lines 132, 134, 136, 138, 144 and 146 to arelay 148a thereby closing a normally open relay contact 148b. In thismanner, an alternate holding circuit is completed from the powerterminal 150 through lines 132, 134, normally closed contacts 152b and154b and normally open contact 148b, and lines 144 and 140 to thesolenoid valve 142 so that the air cylinder 12 will continue downwardmovement of the anvil 16 after the start button 130 has been released.

FIGURE 1 shows a pin 164 which is carried by the upper anvil 16 andmoves between the arms of a guide bracket 166 which is afiixed to amounting plate 168 by a purality of screws 170. There is also provided amicroswitch 172 which is operable by a pivotally movable actuator rod174, thelatter extending into the path of the pin 164 as the upper anvil16 descends toward the lower anvil plate 114. Accordingly, before theupper anvil 16 reaches the lower end of its stroke, the pin 164 willengage the rod 174 and close the switch 172. As shown in FIGURE 4, theclosing of the switch 172 completes a circuit through lines 132, 134,136, 176, time delay relay 152a, function switch 118, line 178, switch172 and line 162 to the solenoid valve 142, while at the same timeenergization of time relay delay relay 152a opens normally closedcontact 15% in the previously described cirluit to the valve 142.

Accordingly, after closing of the microswitch 172, the upper anvil 16will continue down to the lower end of its stroke and will remain in itsdown position under the force of the air cylinder 12 for a time intervalcontrolled by the time delay relay 15 2a. In the particular embodimentwhich is being described by way of example only, the time delay relay152a can be set for any desired time interval between 0 and 60 seconds.When the selected time expires, the time delay relay 152a will opencausing the solenoid valve 142 to admit air to the opposite end of thecylinder 12 thereby returning the upper anvil 16 to its originalretracted position. However, in the test being described, otheroperations occur before the retraction of the upper anvil, as will bedescribed hereinbelow.

It will be noted from FIGURE 4 that upon the closing of the microswitch172, normally open contact 1520 is closed thus completing a circuitthrough the heating element 179 of a normally open delay tube 180, thecircuit being from power terminal 150 through lines 132, 134, 136, 182,184, 178, 160, 158 and 186 to power terminal 150. Thus, after apredetermined time interval, the element 179 will heat sufficiently toclose the tube 180, causing power to be applied to a second four Waysolenoid valve 188 which controls the air cylinder 44. There is shown anair supply valve 190, a regulator 192, a pressure gage 194, a shut-01fvalve 196 leading to the solenoid valve 188, an exhaust line 198 forcylinder 44, a regulator 200, pressure gage 202 and shut-off valve 196'in a line 204 leading to the solenoid valve 142, and an exhaust line 206for the air cylinder 12.

It will be understood that the valve 188 is normally positioned so as tomaintain the piston rod 48 and rack 46 in their retracted or left-handpositions as viewed in FIGURES 1 and 2, and when the delay tube 130closes so as to apply power to the valve 188, air is admitted to thecylinder 44 so as to push the rack 46 to the right until the end thereofengages the end of the adjustable stop screw 52. In this manner, thelower anvil 42 and lower anvil plate 114 are rotated through apredetermined angle, while the upper anvil 16 remains pressed againstthe lower anvil plate. In the particular example being described, thedelay tube 180 is not adjustable, but of course a delay tube is selectedhaving a desired prede- 4 termined time delay, such time delay being thetime interval between the closing of the microswitch 172 by thedescending anvil 16 and the actuation of the valve 188 to initiaterotation of the lower anvil plate 114. One example of a suitable tube180 is a two-second delay tube. It takes approximately one-half secondfor the upper anvil 16 to engage the lower anvil plate 114 aftertripping the microswitch 172, and thus in the example described therewould be a delay of approximately one and onehalf seconds between thetime the upper anvil 16 engages against the lower anvil plate 114 andthe time that rotation of the lower anvil plate is initiated.

As previously described, the time interval between the closing of themicroswitch 172 and the retraction or raising of the upper anvil 16 isdetermined by the time delay relay 152a which can be set for any desiredinterval between and 60 seconds. In the example being described, therelay 152a would be set for a time in excess of two seconds so as toassure that rotation of the lower anvil plate 114 is completed beforethe upper anvil 16 is raised. When the time delay relay 152a runs out,power is removed from the solenoid valve 142 and air is admitted to thecylinder 12 to raise the upper anvil 16, the anvil being suddenlysnapped upwardly by the inrush of air. As the anvil 16 moves upwardly,the microswitch 172 is opened so as to remove power from the solenoidvalve 188. Consequently, the valve 188 returns to its normal positionthereby returning the rack 46 to its retracted position so as to causethe lower anvil 42 and anvil plate 114 to be rotated back to theiroriginal positions.

As described earlier herein, a test is conducted by attaching a testsample of coated paper to the blanket material 116 at the bottom of theupper anvil 16, and a piece of dark material such as black plasticelectricians tape is attached to the top of the lower anvil plate 114, adrop of aqueous solution such as lithographic fountain solution beingplaced on the black tape. During a test, the upper anvil 16 moves downinto engagement with the lower anvil plate 114 pressing the test sampleagainst the black tape and spreading the moisture over the contact areawhile squeezing out any excess moisture. Thereafter, the lower anvilplate 114 is rotated through a predetermined angle, e.g., up to twocomplete revolutions, so as to produce rubbing or frictional forcesbetween the test sample and the black tape. A predetermined time aftercompletion of the rotation of the lower anvil plate 114, the upperanvil16 is suddenly moved upwardly away from the lower anvil platethereby separating the test sample from the black tape and producingpick forces therebetween, such pick forces being dependent upon thespeed at which the upper anvil is retracted. After retraction of theupper anvil 16, the lower anvil plate 114 is rotated back to itsoriginal position.

It will be understood from the foregoing that rubbing or frictionalforces are first created between the test sample and the piece of blacktape, and thereafter the pick forces are produced, the sequence beingthe same as actually occurs in a printing operation. Moreover, it ispossible through adjustment of the time delay relay 152a to control thetime interval between the application of the rubbing forces and theapplication of the pick forces so as to approximate the time intervalwhich actually occurs in a printing operation where the rubbing forcesare applied as the paper web moves through a nip defined between a pairof blanket rolls and the pick forces are applied as the paper web leavesthe nip and is separated or peeled from the blanket surfaces. Thus, inaccordance with the method and apparatus of the present invention, thetest sample is subjected to both frictional or rubbing forces and pickforces in a timed sequence closely duplieating conditions which actuallyexist in a printing operation. As a result, the test provides anextremely accurate indication of the piling propensity of the paperbeing tested, even where the paper is of a type which exhibits a highdegree of resistance to piling produced by pick forces and a lowresistance to piling produced by rubbing forces, or vice versa.

The foregoing description explains the manner of controlling the timeintervals between the various operations in a test as well as the mannerof controlling the degree of rotation of the lower anvil plate 114. Inaddition, it should be noted that by adjusting the valve 196 in the aircircuit for the cylinder 44, it is possible to control the speed ofrotation of the anvil plate 114. In a similar manner, by adjusting thevalve 196' in the air circuit to the cylinder 12, it is possible tocontrol the liftolf speed, i.e., the speed at which the upper anvil 16moves upwardly away from the lower anvil plate 114. The latter speeddetermines the severity of the pick forces which are produced, and incertain situations if desired the liftoff speed may be set very low sothat the pick forces are negligible, in which case the resultant test isessentially a wet rub test. It will further be noted that in specialsituations the valve 196 in the air circuit to the cylinder 44 may beclosed, in which case the lower anvil plate 114 will not rotate and theresult will be a wet pick test without rubbing forces. Accordingly, theapparatus of the present invention can be used to provide only a wetpick test or only a wet rub test, although the essential objective is toprovide a combination pick-rub test.

Upon carrying out a pick-rub test in the manner described above, acertain amount of the coating material on the test sample will bedeposited on the piece of black plastic tape against which the testsample was engaged. The coating material is more or less white in colorand thus is readily visible on the black tape. Consequently, the pilingpropensity of the test sample can be determined by visually or opticallycomparing the black tapes to standards for numerical or similar grading,and the tape itself may then be attached to a record or report since thecoating deposits on the tapes will readily adhere thereto so as to forma permanent visual record. One advantageous technique is to use abrightness meter for measuring the reflectance of the black tapes, andvarious known types of instruments can be used for this purpose, itbeing understood that the more coating there is on the tape the greaterwill be the reflectance reading. Another technique is to provide apreviously prepared set of calibrated samples so that the test specimentape may be compared with the set of samples to obtain a rating as topiling propensity.

The apparatus described herein is also adapted for penetration testingof paper test specimens. In order to conduct a penetration test, thefunction switch arm is positioned to engage the upper terminal 122,thereby bringing into the circuit an interval timer 208, and the airvalve 196 is closed so as to prevent rotation of the lower anvil plate114. For purposes of a penetration test, the piece of blanket material116 is removed from the upper anvil 16, a test sample is secureddirectly to the bottom of the upper anvil, and a drop of moisture isplaced on the top of the lower anvil plate 114. The push button 130 isdepressed causing the upper anvil 16 to move downwardly against thelower anvil plate 114 in the manner previously described due to theholding circuit established to the solenoid valve 142 through thenormally closed contacts 152!) and 154b and the normally open contact148b. As the moisture begins to penetrate the test sample, a currentflow is established, the circuit being from one side of a battery 210-through line 212 to the lower anvil plate 114, through the test specimento the upper anvil 16, lines 158 and 214, and through voltage sensitiverelay 154a and milliammeter 216 to the opposite side of the battery 210.

It will further be noted that as the descending upper anvil 16 closesthe microswitch 172 in the manner previously described, power is appliedto the interval timer 208 to initiate the beginning of a measured timecycle. As the test sample deteriorates and moisture penetrationtherethrough increases, the current flow through the sample and throughthe voltage sensitive relay 154a increases until a predeterminedmagnitude of current flow pulls in the relay 154a and opens the normallyclosed contact 154b, thereby removing power from the solenoid valve 142and causing retraction of the upper anvil 16. As the anvil 16 retractsupwardly, it opens the microswitch 172 breaking the circuit through theinterval timer 208 so as to stop the latter. Accordingly, the reading onthe timer 208 indicates the time required to develop a predeterminedamount of penetration of the test sample. The interval timer 208measures the time from the closing of microswitch 172 to the openingthereof, and such interval is dependent upon the time required todevelop an amount of penetration through the test sample so as toproduce a predetermined current flow therethrough sufiicient to pull inthe voltage sensitive relay 154a.

While we have described our invention in certain preferred forms, we donot intend to be limited to such forms, except insofar as the appendedclaims are so limited, since modification coming within the scope of ourinvention will readily occur to those skilled in the art, particularlywith our disclosure before them.

We claim:

1. Apparatus for determining the piling propensity of paper or the likecomprising, in combination, first and second anvil means positioned inaxial alignment and in opposed facing relation to one another, one ofsaid anvil means having a test specimen secured to the end thereofduring a test cycle, one of said anvil means also being movable axiallytoward and away from the other anvil means and one of said anvil meansbeing rotatable about its longitudinal axis relative to the other anvilmeans, first actuating means for moving the axially movable one of saidanvil means toward the other anvil means and into engagement therewithunder pressure, and second actuating means operable during suchengagement for rotating the rotatable one of said anvil means through apredetermined angle relative to the other anvil means, said firstactuating means being operable subsequent to said rotation to eifectsudden separation of said first and second anvil means.

2. The invention of claim 1 where said first anvil means is movabletoward and away from said second anvil means, and where said secondanvil means is rotatable about its longitudinal axis relative to saidfirst anvil means.

3. The invention of claim 1 including adjustable stop means forcontrolling the angle through which the rotatable anvil means is rotatedduring a test cycle.

4. The invention of claim 1 including first timing means associated withsaid first actuating means for controlling the time of engagementbetween said first and second anvil means, and second timing meansassociated with said second actuating means for initiating rotation ofthe rotatable anvil means a predetermined time after initiation of saidengagement and before termination of said engagement.

5. The invention of claim 4 where said first timing means is adjustablein order to adjust the duration of said engagement and thereby adjustthe time interval between the rotation of the rotatable anvil means andthe separation of said first and second anvil means.

6. The invention of claim 1 where said first and second actuating meanscomprise first and second double-acting air cylinders, and where saidsecond actuating means further includes gear means for rotating therotatable anvil means and rack means actuated by said seconddoubleacting air cylinder and in mesh with said gear means for drivingthe latter.

7. The invention of claim 6 including an adjustable stop positioned forengagement by said rack means so as to limit the linear stroke thereof,said stop thereby serving to control the angle of rotation of therotatable anvil means during a test cycle.

8. The inventin of claim 6 including first adjustable valve meanslocated in an air circuit to said first doubleacting air cylinder forcontrolling the speed at which one of said anvil means is moved towardand away from the other of said anvil means, and second adjustable valvemeans located in an air circuit to said second doubleacting air cylinderfor controlling the speed at which the rotatable anvil means is rotatedby said rack means.

9. Apparatus for determining the piling propensity of paper or the likecomprising, in combination, lower anvil means mounted for rotation abouta vertical axis and having a substantially fiat horizontal top surface,upper anvil means disposed above said lower anvil means in axialalignment therewith and having a substantially fiat horizontal bottomsurface in opposed facing relation to said top surface, one of saidsurfaces having a test specimen secured thereto during a test cycle,said upper anvil means being movable downwardly and upwardly toward andaway from said lower anvil means, first air cylinder means for rotatingsaid lower anvil means through a predetermined angle, second aircylinder means for moving said upper anvil means downwardly intoengagement under pressure with said lower anvil means and subsequentlyupwardly away from said lower anvil means, and first and second timingmeans associated with said first and second air cylinder meansrespectively, said second timing means serving to control the time ofengagement between said upper and lower anvil means, and said firsttiming means serving to initiate rotation of said lower anvil means apredetermined time after initiation of said engagement and beforetermination of said engagement.

10. The invention of claim '9 including rack and gear means actuated bysaid first air cylinder means for rotating said lower anvil means, andadjustable stop means for controlling the stroke of said rack means inorder to control the angle of rotation of said lower anvil means.

11. The invention of claim 9 where said second timing means isadjustable in order to adjust the duration of said engagement andthereby adjust the time interval between the rotation of said loweranvil means and the upward retraction of said upper anvil means.

12. A method of determining the piling propensity of coated paper or thelike comprising the steps of pressing a test specimen of the paper intoengagement with a fiat piece of dark-colored material which is wettedwith a small amount of aqueous solution, maintaining a predeterminedforce on said specimen to hold the same under pressure against saiddark-colored material for a predetermined time, rotating said specimenand said darkcolored material through a predetermined angle relative toone another about an axis perpendicular to the plane of said specimen,suddenly separating said specimen and said dark-colored materialsubsequent to the completion 1 l 1 2 of said rotation, and measuring theamount of coating References Cited galnaslferred from said specimen tosaid dark-colored ma- UNITED STATES PATENTS 13. A method according toclaim 12 Where the separa- 2,815,658 12/1957 Press 73-7 tion of saidspecimen and said dark-colored material is 5 3129586 4/1964 Allen al 73150 XR carried out a selected predetermined time after said relativerotation of said specimen and said dark-colored ma- CLEMENT SWISHERActmg Examiner terial. JEFFREY NOLTON, Assistant Examiner.

